An air compressor improves the dustproof performance of an intake path to a crankcase. The air compressor includes a compression assembly that reciprocates a piston in a cylinder to produce compressed air, a crankcase accommodating the compression assembly and having an inner inlet to allow outside air to be drawn, a filter located in the crankcase and covering the inner inlet from outside, a filter cover having an outer inlet and covering the filter from outside, and a dust cover covering the filter cover from outside, covering the outer inlet, and including an outer circumferential portion. The outer circumference portion and the filter cover have a space to draw outside air between the outer circumference portion and the filter cover.